SHARE-BASED COMPENSATION - Other Options Disclosures (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands |
3 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Other Options Disclosures [Line Items] | ||||
| Fair value per option issued | $ 4.33 | $ 0 | $ 0 | |
| Intrinsic value of options exercised | $ 829 | $ 60 | $ 1,678 | |
| Cash received from exercise price of options exercised | 153 | 42 | 265 | |
| Tax benefit from options exercised | $ 220 | $ 21 | $ 636 | |
| Number of options issued | 686 | 0 | 0 | |
| Intrinsic Value Per Share Upon Exercise | $ 7.33 | $ 7.24 | $ 12.21 | |
| Maximum [Member] | ||||
| Other Options Disclosures [Line Items] | ||||
| Exercise price range of options issued | $ 11.31 | $ 2.02 | $ 11.31 | $ 11.69 |
| General vesting period in years | 10 years | 10 years | 10 years | |
| Minimum [Member] | ||||
| Other Options Disclosures [Line Items] | ||||
| Exercise price range of options issued | $ 1.34 | $ 1.34 | $ 1.34 | $ 1.34 |
| General vesting period in years | 1 year | 1 year | 1 year | |